Remote Structure Defect Detection via Displacement Separation
Solution Overview
Problem
Existing methods for remotely detecting defects in structures, such as cracks or internal cavities in concrete structures, face challenges due to the combination of in-plane and out-of-plane displacements caused by loading, leading to accuracy degradation and increased costs, particularly when requiring additional video devices and complex operability for side imaging.
Innovation Solution
A status determination device and system that calculates a two-dimensional spatial distribution of displacement from time-series images before and after loading, separates the out-of-plane displacement, and identifies defects using a depth moving amount calculation unit, displacement separation unit, and abnormality determination unit, allowing for remote detection without contact and reduced costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single video device captures images of the structure surface, then costs are reduced and operability is simplified, but out-of-plane displacement cannot be measured accurately
Solution Approach 1:
The patent transforms the measurement problem from a three-dimensional physical space requirement (multiple cameras at different positions) to a two-dimensional image processing problem. By capturing surface images before and after loading and analyzing pixel displacement in the image plane, the system can calculate out-of-plane displacement components through image correlation algorithms, eliminating the need for additional side-viewing video devices.
Solution Approach 2:
The patent replaces the mechanical/optical measurement system (multiple video devices positioned to capture side views) with an image processing and computational system. By using digital image correlation techniques to analyze pixel movements in surface images, the system computes displacement components including out-of-plane movements without requiring physical access to capture side views of the structure.
2Measurement precision
If two video devices are used to capture side images for out-of-plane displacement measurement, then measurement accuracy is improved, but costs increase and operability becomes complex
Solution Approach 1:
The patent extracts only the necessary information (surface displacement patterns) from the structure by capturing images of the surface before and after loading. By focusing measurement on the accessible surface area and using image correlation to infer three-dimensional displacement components, the system eliminates the need for complex side-viewing arrangements and difficult positioning operations.
Solution Approach 2:
The patent enables the surface images themselves to provide all necessary measurement information. The displacement patterns visible on the structure surface contain encoded information about out-of-plane movements, which can be decoded through image processing algorithms without requiring additional measurement devices or complex operational procedures.
3Measurement precision
If two video devices are used to capture side images for out-of-plane displacement measurement, then measurement accuracy is improved, but costs increase
Solution Approach 1:
The patent makes the single video device perform multiple functions: capturing surface geometry, measuring in-plane displacements, and inferring out-of-plane displacement components. By using digital image correlation analysis on the captured images, the system extracts comprehensive three-dimensional displacement information from a single viewing position, eliminating the need for additional specialized measurement devices.
Data Source
AI summary
The purpose of the present invention is to accurately detect, from a remote location without contact, a structure's defects such as cracking, separation, and internal cavities by distinguishing therebetween. The status determination device includes: a displacement calculation unit that, from time-series images of a structure surface before and after loading application, calculates a two-dimensional spatial distribution of a displacement of the time-series images; a depth moving amount calculation unit that calculates a moving amount of the structure surface in a normal direction due to the loading application, from the two-dimensional spatial distribution of the displacement of the time-series images; a displacement separation unit that calculates a correction amount based on the moving amount, and separates a two-dimensional spatial distribution of a displacement of the structure surface, by subtracting the correction amount from the two-dimensional spatial distribution of the displacement of the time-series images; and an abnormality determination unit that identifies a defect of the structure, based on comparison of the two-dimensional spatial distribution of the displacement of the structure surface and the moving amount, with a spatial distribution of a displacement having been prepared in advance and a threshold value for the moving amount.